Tanning and fat liquoring method

ABSTRACT

A phenolic compound having a long-chain alkyl radical or a longchain alkenyl radical is used as a tanning and fat-liquoring agent in addition to ordinary tanning agents in tanning of hides and skins. This invention relates generally to the art of processing animal hides and skins and more particularly to a new and improved method and fat liquoring agents for tanning hides and skins.

United States Patent Shimizu et al.

[451 Mar.2l, 1972 [54] TANNING AND FAT LIQUORING METHOD [72] Inventors: Teisuke Shimizu, Tokyo-to; Atsuo Sasaki, Omiya-shi; Shigeo Nagaki, Urawa-shi, all

[21] App1.No.: 730,660

[30] Foreign Application Priority Data June 13, 1967 Japan, ..42/37285 [51] Int. Cl.. ..Cl4c 9/02, C14: 9/04 [58] Field of Search S/94.22, 94.23, 94.33

[56] References Cited UNITED STATES PATENTS 2,205,950 6/1940 F1ett...- ..8/94.23X

3,102,772 9/1963 Robinson ..8/94.23X

FOREIGN PATENTS OR APPLICATIONS 464,443 4/1950 Canada ..8/94.23

OTHER PUBLICATIONS Merck Index, 7th Edition, 1960, p. 77 (Anacardic Acid) and page 1085 (Urushiol).

Primary ExaminerGeorge F. Lesmes Assistant ExaminerI-I. Wolman Attorney-Wenderoth, Lind & Ponack ABSTRACT A phenolic compound having a long-chain alkyl radical or a long-chain alkenyl radical is used as a tanning and fat-liquoring agent in addition to ordinary tanning agents in tanning of hides and skins.

This invention relates generally to the art of processing animal hides and skins and more particularly to a new and improved method and fat liquoring agents for tanning hides and skins.

9 Claims, No Drawings TANNING AND FAT LIQUORING METHOD Heretofore, various methods for tanning hides and skins have been practiced, representative methods being the chrome tanning, vegetable tanning, and formaldehyde tanning methods. In each of these methods, a fat-liquoring and stuffing agent is added in the tanning process with the aim of obtaining soft tanned leather.

However, since fat-liquoring and stuffing agents (hereinafter referred to as fat-liquoring agents) used heretofore have invariably been of the fatty oil type or of the type containing synthetic, hydrocarbon chain derivatives, they have had low affinity with respect to hides and skins, whereby these fat-liquoring agents have had a tendency to be readily desorbed from the hides and skins. Consequently, tanned leathers thus produced have often had the disadvantageous tendency of hardening during use and readily developing cracks.

It is an object of the present invention to overcome the' above described difficulty by providing a new tanning method and agents whereby leathers having highly desirable and durable characteristics can be produced.

More specifically, an object of the invention is to provide a group of new fat-liquoring agents to be .used with ordinary tanning agents to produce leather, which fat-liquoring agents have substantial tanning effect in addition to their excellent fat-liquoring effects, and which, as fat-liquoring agents, are not readily desorbed from the finished leather.

According to the present invention, briefly summarized, there is provided a tannable fat-liquoring agent containing as its principal component a phenolic compound having a longchain alkyl radical or a long-chain alkenyl radical attached thereto.

According to the present invention there is further provided a method for tanning hides and skins with the ordinary tanning agents, which method is characterized by the-use of, in addition to the ordinary tanning agents, a tannable fat-liquoring agent as designated above and as described more fully hereinafter.

The nature, principle, details, and utility of the invention will be more clearly apparent from the following detailed description beginning with a basic and general consideration and concluding with description of preferred embodiments of the invention.

A feature of the method of the invention lies in the use of compounds such as monovalent or bivalent long-chain alkylor long-chain alkenylphenols and long-chain alkylor longchain alkenyl-phenol having a carboxyl group as tannable fat-liquoring agents as described more fully hereinafter, These compounds can be represented by the following general formula.

Long-chain alkyl or alkenyl derivative of monovalent phenol.

OH Longchain alkyl or alkenyl derivative of bivalent phenol.

Phenolic earbo He sold havi aio -chalna i 0 Don or alkenyl rad i eal. ng ng my Bivalent henolle carboxyllc acid havl a lon R Co OH chain al yl radical or alkenyl radical. n8 8 In the above formulas, R represents a long-chain alkyl radical or a long-chain alkenyl radical.

Examples of compounds corresponding to the above represented compound form are octylphenol and nonylphenol among those produced synthetically and cashew nut shell liquids, urushiol, and laccol among those obtained naturally.

Among cashew nut shell liquids, there is the class obtained by cold pressing or by solvent extraction and the class obtained by heat elution. The former class contains anacardic acid as the principal component and also approximately 10 percent of cardol, which is a bivalent phenol-derivative. These two components may be represented as follows.

OH OH OOOH , (anacardie acid) (cardol) The latter class of cashew nut shell liquid obtained by a hot oil 5 bath method contains cardanol and cardol as principal components. While cardanol may be represented by the general formula 55 which may be represented by the following molecular formulas.

As described above, the fat-liquoring agent used in the process according to the invention is invariably a phenolic compound having a long-chain alkyl radical or alkenyl radical. We have found that when a compound of this type is used as a fat-liquoring agent for hides and skins, the phenolic radical OH is linked with the active group (with) in the proteins which are constituents of a hide or skin to accomplish tanning, and, at the same time, the long-chain alkyl or alkenyl radical functions as a fat-liquoring agent to cause softening of the hide or skin. We have found further that when a COOH radical is present, it forms a strong complex compound with the chromium in chrome leather and remains for a long time in the leather without separating therefrom.

That is, the fat-liquoring agent used in the process of the invention, differing from those used heretofore, exhibits not only a fat-liquoring effect but also a tanning effect with respect to hides and skins. Therefore, it may be more appropriate to call this agent as a tannable fat-liquoring agent." Practical use of such tannable fat-liquoring agents has been made possible for the first time by the present invention.

Since a tannable fat-liquoring agent according to the invention is capable of effectively accomplishing both tanning and fat-liquoring as described above, it can be used in a step of a fat-luquoring process stop subsequent to an ordinary tanning, or it may be mixed with an ordinary tanning agent and used in one process step to accomplish simultaneously both tanning and fat-liquoring. The use of this tannable fat-liquoring agent in a separate fat-liquoring step and its mixed use as a tanning agent are herein referred to generically by the term joint use.

Since the process of tanning hides or skins is generally carried out in an aqueous solution, it is necessary to disperse or dissolve the tannable fat-liquoring agents in water. For this purpose, in the case of alkyl or alkenyl derivatives of monovalent or bivalent phenol, each derivative is converted to a phenolate of sodium or potassium which is readily dispersible in water. When necessary, an alcohol can be further added to increase the solubility of the agent in water. When a suitable dispersing agent is used, the alkyl or alkenyl derivative in its original state can be dispersed directly in water.

A phenolic carboxylic acid having a long-chain alkyl radical or a long-chain alkenyl radical as, for example, a cashew nut shell liquid (cold pressed) which has not yet been decarboxylated and contains anacardic acid as the main constituent, can be rendered soluble in water by converting it to a basic salt of sodium, potassium, organic amines, and ammonia.

We have found that, in order to obtain a satisfactory softening effect with respect to hides and skins, a length greater than that corresponding to C, is preferably for the alkyl or alkenyl radical which is a side chain of the phenolic compound.

The use ofthe tannable fat-liquoring agent of the invention as a fat-liquoring agent in a tanning process produces results which have been found to be superior to those attainable through the use of conventional fat-liquoring agents. More specifically, improvements in swelling or plumpness and hand feeling, increase in smoothness of the grain side (or hair side), prevention of poor hide, increase in the fullness of belly, and other desirable results are attained, and, moreover, washable leathers oflow trichlene extraction quantity can be produced.

In order to indicate still more fully the nature and utility of the invention, the following examples of typical procedure are set forth, in being understood that these examples are presented as illustrative only and that they are not intended to limit the scope ofthe invention.

EXAMPLE 1.

A fat-liquoring composition material suitable for use according to the invention was prepared by adding 250 grammes (g.) of methanol to g. of nonylphenol and 300 g. ofa decarboxylated cashew nut shell liquid, adding by dropping 350 g. of a lO-percent aqueous solution of sodium hydroxide to the resulting process batch as the batch was maintained at a temperature of degrees C. and agitated, and continuing the agitation at the same temperature for 30 minutes after completion ofthe dropping.

Separately, a hide which had been unhaired, delimed, pickled, and chrome tanned by ordinary processes was neutralized in a neutralising agent containing bicarbonates as principal agents until the cross section of the hide exhibited completely a blue color by B.C.G., and the leather was then dyed.

Then, as 100 parts of the leather thus dyed and placed in 100 parts of water (at degrees C.) was agitated therewith, six parts of the afore-described fat-liquoring preparation was added to the leather and water by dropping, and the agitation was continued until the fat-liquoring material was absorbed in the leather. The leather was then thoroughly washed with water, dried, and finished in the conventional manner.

EXAMPLE 2.

300 g. of methanol was added to 390 g. ofa cashew nut shell liquid which had not been decarboxylated, and then, at 50 degrees C., 60 g. of 28-percent ammonia water and 10 g. of a lO-percent aqueous solution of sodium hydroxide was further added by dropping. The resulting batch was agitated and maintained at the same temperature for one hour after completion of the dropping, whereupon a fat-liquoring composition was obtained.

Separately, lOO parts of a leather which had undergone chrome tanning, neutralization, and tannin retanning by conventional process steps and parts of water (at 100 degrees C.) were placed in a drum and rotated. A solution prepared beforehand by dissolving 1.5 parts of sulphonated neats foot oil (known also as beef foot oil) and L5 parts of the aforedescribed fat-liquoring composition in a suitable quantity of water was injected into the drum through an inlet passage in the side shaft of the drum, and the rotation of the drum was continued for approximately 30 minutes. The leather thus treated was then washed with water, dried, and finished in the conventional manner.

EXAMPLE 3.

A fat-liquoring composition suitable for use according to the invention was prepared by adding 200 g. of methanol to 300 g. of a cashew nut shell liquid which had not been decarboxylated, 30 g. of a decarboxylated cashew nut shell liquid, and 50 g. of urushiol, dropping 75 g. of triethanolamine and 40 g. of a lO-percent aqueous solution of sodium hydroxide into the resulting process batch as it was maintained at a temperature of 60 degrees C. and agitated, and maintaining the resulting batch at the same temperature for seven hours after completion of the dropping step.

Separately, fur pelts which had been subjected respectively to formalin tanning and alum tanning were coated on their flesh sides, after surplus water had been drained off, with a fatliquoring agent consisting of a mixture of 100 parts of the afore-described fat-liquoring composition and 5O parts of octylphenol and were dumped for 24 hours with their flesh sides in mutual contact. Thereafter, the pelts were air dried and seasoned and staked by conventional methods whereupon a fur of excellent soft feeling was obtained.

EXAMPLE 4.

A previously prepared mixture of five parts of a cashew nut shell liquid which had not yet been decarboxylated and five parts of phosphorated castor oil was applied by hand on 100 parts of hide which had been tannin tanned by the conventional process and then drained of water. The resulting leather was then air dried and finished by a known process.

EXAMPLE 5 A fat-liquoring composition for use according to the invention was prepared by adding five g. of Noigen EA-15l (a nonionic surface active agent manufactured by Daiichi Kohgyoh Seiyaku K.K., Japan) at room temperature to 500 g. of an undecarboxylated cashew nut shell liquid and thoroughly mixing the resulting mixture.

Separately, 100 parts of skins of small animals such as lamb skin and dog skin which had been unhaired, bated, and degreased by conventional procedures were subjected to shipping with 100 parts of water, 0.5 part of sulphuric acid, and 1 part of formic acid and rotated for 30 minutes in a drum. Then 7.5 parts of a 35-percent aqueous solution of formaldehyde was added to the process batch, and the drum was rotated for a further two hours. Soda ash was then added to the batch to adjust the pH value of the batch to 4.5, and the the skins were taken out of the drum and thoroughly by washed with water. v

100 parts of the skins thus treated, 100 parts of water (at 50 degrees C.), and five parts of the fat-liquoring composition described above were placed in a drum and rotated for two hours. The skins were then taken out of drum, lightly squeezed, dried in the squeezed state, and left for 48 hours to cause the fat-liquoring composition to react thoroughly. Thereafter, surplus 'unreacted components were removed, and the skins were dried and subjected to stocking, whereupon very soft leather of light yellowish brown color, which was washable with soap water, was obtained.

EXAMPLE 6.

To 221 g. of nonylphenol and 34 g. of an undecarboxylated cashew nut shell liquid, 200 g. of menthanol was added, and, as the resulting batch was maintained at a temperature of 40 degrees C. and agitated, 280 g. of a -percent aqueous'solution of potassium hydroxide was added thereto by dropping.

. The agitation was thereafter continued for two hours at the same temperature, whereupon a fat-liquoring composition for use according to the invention was obtained.

Separately, 100 parts of raw hide which had been unhaired, delimed, and bated by conventional procedures was subjected to pickling for one hour in a solution of 10 parts of common salt and l part of sulphuric acid in 100 parts of water. The resulting hide was then drained of water and drum treated for a period of from two to three hours in a solution of parts of glutaraldehyde (ZS-percent aqueous solution) in 100 parts of water. Thereafter, 10 parts of the above described fat-liquoring composition was introduced into the drum through a drum side shaft hole, and the drum was rotated for seven hours. The hide was then washed with water, .dried, seasoned, and staked.

In order to indicate still more fully the utility of the present invention, the results of tests for comparison of the method of the invention and a conventional method are set'forth in the following table. The conventional method comprised chrome tanning the hide by an ordinary procedure and then treating the hide with sulphonated neats foot oil as a fat-liquoring agent.

Tanning with fabliquoring agent according to the Tanning with only sulphonated neat's foot oil of same 2) Tests for Example 3 were omitted because the product is a fur.

It should be understood, of course, that the foregoing disclosure relates to only preferred embodiments of the invention and that it is intended to cover all changes and modifications of the examples of the invention herein chosen for the purposes of the disclosure, which do not constitute departures from the spirit and scope of the invention as set forth in the appended claims.

We claim:

I. A method of tanning hides and skins to prepare a leather material which comprises employing in the tanning process, and in addition to the ordinary tanning agents, a fat-Iiquoring step utilizing a compound of the formula R (C 0.0H)m

wherein R is a long-chain-alkyl radical or a long-chain alkenyl radical, is l or 2 and m is 0 or 1.

2. The method as claimed in claim 1, wherein said compound'is converted to a water soluble or dispersible salt prior to use.

3. The method as claimed in claim 2, wherein R contains 5-l 7 carbon atoms.

4. The method as claimed. in claim 2, wherein said compound is selected from the group consisting of octylphenol, nonylphenol, cashew nut shell liquids, urushiol and laccol.

5. The method as claimed in claim 4, wherein the cashew nut shell liquid is anacardic acid, cardol or cardanol.

6. The method as claimed in claim 2, wherein the salt is a sodium, potassium, organic amine or ammonium salt.

7. The method as claimed in claim 1 in which said compound is used in a fat-liquoring process following an ordinary tanning process.

8. The method as claimed in claim 1 in which said compound is mixed with at least one ordinary tanning agent, and the resulting mixture is used in one step to accomplish simultaneously both tanning and fat-liquoring.

9. The method as claimed in claim 1 in which said compound is selected from the group consisting of long-chain alkyl and alkenyl derivatives of monovalent phenol, long-chain alkyl and alkenyl derivatives of bivalent phenol, phenolic carboxylic acids having long-chain alkyl or alkenyl radicals, and bivalent phenolic carboxylic acids having long-chain alkyl or alkenyl radicals. 

2. The method as claimed in claim 1, wherein said compound is converted to a water soluble or dispersible salt prior to use.
 3. The method as claimed in claim 2, wherein R contains 5-17 carbon atoms.
 4. The method as claimed in claim 2, wherein said compound is selected from the group consisting of octylphenol, nonylphenol, cashew nut shell liquids, urushiol and laccol.
 5. The method as claimed in claim 4, wherein the cashew nut shell liquid is anacardic acid, cardol or cardanol.
 6. The method as claimed in claim 2, wherein the salt is a sodium, potassium, organic amine or ammonium salt.
 7. The method as claimed in claim 1 in which said compound is used in a fat-liquoring process following an ordinary tanning process.
 8. The method as claimed in claim 1 in which said compound is mixed with at least one ordinary tanning Agent, and the resulting mixture is used in one step to accomplish simultaneously both tanning and fat-liquoring.
 9. The method as claimed in claim 1 in which said compound is selected from the group consisting of long-chain alkyl and alkenyl derivatives of monovalent phenol, long-chain alkyl and alkenyl derivatives of bivalent phenol, phenolic carboxylic acids having long-chain alkyl or alkenyl radicals, and bivalent phenolic carboxylic acids having long-chain alkyl or alkenyl radicals. 